The invention relates to a modified construction machine for clearing all types of landmines and which with simple modifications is also suitable for clearing vegetation such as bushes and scrub in, e.g., mine-laid areas.
During the Second World War special apparatus, so-called flail units, were developed for use in the work of mechanical mine clearance. A unit of this kind traditionally comprises a rotor or shaft secured between two fixed arms arranged on the front of a carrier machine. Chains with weights at the end thereof are secured to the rotor. The intention is that the mines are to be detonated or crushed when the rotor rotates and the chains and their weights beat the ground. The mines may be anything from anti-personnel mines of from about 200 g to anti-tank mines having a charge of up to several kilos of high explosive (HE). To be able to withstand the impact of the explosions, the first carrier machines were modified military tanks. More recently, other types of vehicles, for example, tractors and large construction machines, have been used as carrier machines for the flail unit. The traditional flail units are effective and practical in use. However, the operation of the unit calls for substantial engine power, especially when it is desirable to run the rotor at high speed and work deep in the ground. This, taken in conjunction with the fact that the carrier machine must be equipped with the necessary armour plating and personnel protection, means that the machines concerned are very powerful, bulky, heavy and of poor manoeuvrability.
One example of known apparatus for clearing mines where the flail unit is mounted on a civilian vehicle is the Danish machine Hydrema, a machine equipped with two engines and weighing about 16 tonnes. However, probably the most common of these vehicles today is the Aardwark J.S.F.U. Mk. III that is based on a large Ford tractor and weighs about 14 tonnes.
The main problem with the first flail units was that mines located in sunken parts of the terrain were not detonated by the flails that were designed to xe2x80x9csweepxe2x80x9d at a constant height above ground level and did not follow the surface contour of the terrain. To eliminate this problem, a counterweight was apparently fastened on the rear end of the flail arm on the mine clearance apparatus Sherman Crab Mark II in order to ensure that the flail was xe2x80x9cbalancedxe2x80x9d above a point. In this way, it was believed that it was possible to maintain the rotor arm and the chains at a constant height above ground level.
Another example of prior art is taught in U.S. Pat. No. 4,765,221, which describes a tank-like mine clearance apparatus equipped with a rotating flail arrangement. As further examples of traditional mine clearance apparatus, reference can be made to GB Patent Application 2 126 958 A, WO 93/11402 and U.S. Pat. No. 5,007,325 (Aardwark). The Aardwark machine apparently has a flail unit that xe2x80x9cfloatsxe2x80x9d at the desired height above the terrain because of the impacts of the flail chains against the ground, thereby ensuring greater effectiveness when the mines are buried. However, the protective shield is mounted on wheels in order to follow the surface of the ground, and the teaching of this document does not outline any Technical measures that will bring about an effect similar to that caused by the mine clearance apparatus according to the invention. This machine is thus in fact a conventional, large, powerful tractor or construction machine.
Lastly, mention may be made of another document, WO 07/46848, which describes a so-called miniflail. This appears to resemble the invention, but is used primarily as a scrub clearer, i.e., it xe2x80x9csweepsxe2x80x9d anti-personnel mines and the like from the surface of the ground. The structural design suggests that it is unsuitable for use against powerful, possibly buried mines and/or explosive charges.
An article relating to a new mine clearing system, the so-called Compact 230 Minecat, was published in Jane""s Defence Weekly on Jul. 21, 1999. The present invention is based on this system. Although the Minecat mine-clearing system has a number of advantages compared to the conventional flail apparatus, it does have a number of drawbacks or deficiencies. For example, the hydraulic system cannot be operated to cause the flail unit to xe2x80x9cfloatxe2x80x9d above and follow the terrain, thereby providing the necessary whipping force against the ground to ensure that mines in depressions, irregularities or the like in the terrain are detonated. Indeed, this was not the intention, and the machine functions basically as a scrub clearer. Consequently, it is not particularly suitable for handling explosives that are larger than so-called anti-personnel mines. Because of.the small size and the low weight of the Minecat clearance apparatus, it was necessary to shape and support the protective shield so as to ensure optimum deflection of the impact of powerful mine detonations, i.e., blast waves, splinters, earth, gravel etc. At the same time, it was necessary to ensure that the vehicle was not exposed to forces causing it to be lifted, overturned or in some other way brought out of its working position Moreover, it has been found that there is a need for a mine clearance apparatus which can also be used for removing vegetation such as bushes and scrub prior to the clearance of the landmines.
The deficiencies and drawbacks of the known mine clearance apparatus are eliminated according to the invention.
The mine clearance apparatus according to the invention weighs about 6.5 tonnes. It is small and compact, and relatively inexpensive to produce and maintain. It does not require any special transport system and lends itself well to transport by plane. Moreover, it can be airlifted by a CH-47 Chinook helicopter. It is also suitable for transport by truck or trailer and can, for example, be driven into a standard ISO container for shipment by sea or rail.